Prepping Your Soil to Transplant Tomatoes

Tomatoes are members of the nightshade family and, being natives of the South America, generally like conditions hot and dry. If you live in a warmer climate, you may already have tomato transplants growing in your garden. In other parts of the country, it will soon be warm enough to transplant. Here are some tips for preparing and managing your tomato beds for maximum efficacy.

Test the Soil

Like Robert Hendrickson says in The Great American Tomato Book, “Gardening without a soil test is like building a house without a blueprint. It can be done, but it’s harder and far more time-consuming in the long run.” Tomatoes prefer a soil pH between 6.0 and 6.8 and need adequate amounts of nitrogen, phosphorus, potassium, and calcium. Test kits should be available at your local garden shop, or send a soil sample to a lab such as the University of Massachusetts Soil and Plant Nutrient Testing Lab. Amend soil as needed.

Amending Soil

The soil should be rich, but with a good balance of nitrogen, phosphorus, and potassium. Too much nitrogen will produce large, leafy plants lacking fruits. Spread compost or aged manure on each spot where a plant will be. You can also sprinkle some crushed eggshells to provide calcium. There are organic fertilizers available designed for tomatoes. These work well as a general fertilizer if you are not able to test the soil.

It is a good idea not to grow tomatoes in the same location year after year, or even to plant them where other nightshade plants (peppers, eggplants, tomatoes) have grown in recent years. Experts suggest a rotation of 3-4 years, but this is not always possible depending on the size of your garden. However, such a garden crop rotation reduces the incidence of disease, which tomatoes are particularly susceptible to.

Buying Transplants

When buying transplants, avoid large, spindly plants already bearing flowers or fruits. Rather, choose healthy young plants with an even height-to-width ratio and of deep green color. Check plants for pests before purchase.

When Planting

Add a generous portion of compost and some crushed eggshells into the hole dug for each plant. If cutworms are a concern, make a circular barrier around the base of your transplants, about an inch into the soil and at least two inches above it. This can be made of a toilet paper tube, paper, or plastic and will prevent cutworms from eating through the stem of your transplants.

Soil Nutrient Problems

If your tomato plants are large and leafy but not producing many fruits, this may be a sign of too much nitrogen in relation to phosphorus and potassium.

Signs of insufficient nitrogen are stunted growth and yellow leaves lower on the plant. Good organic amendments for nitrogen are aged manure, blood-meal, compost, and fish emulsion.

If your plants are stunted and thin with purple undersides on the leaves, this may be a sign of insufficient phosphorus. Good organic sources are phosphate rock, bonemeal, and poultry manure.

If your tomato plants are stunted with yellow-splotched leaves, this may be a sign of insufficient potassium. Good organic sources are granite meal and wood ashes.

Calcium is also important for tomato plant development and disease resistance. Good organic sources are bonemeal, eggshells, ground limestone, and wood ashes.